Reliability Analysis for Effects of Reservoir Water Level Change on Embankment Dam

Abstract:

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This paper is mainly concerned with the saturated-unsaturated seepage analysis of
embankment dams based on unsaturated soil theory and the reliability analysis of embankment dam
based on conception of reliability. The transient seepage due to change of the water level is
calculated using the finite element method based on unifying saturated-unsaturated seepage
governing equations. The transient pore water pressures are then used for stability analyses of
embankment dam considering the effects of suction on shear strength of unsaturated soils.
Meanwhile, combined with reliability computation, the Monte-Carlo stimulation method is used to
calculate the corresponding reliability index dealing with the stochastic features of soil parameters.
The reliability of different water level condition of embankment dams has been analyzed. The
effects of different reservoir water level drawdown and raise speeds on reliability of embankment
dam are discussed.

Abstract: In this paper, in order to overcome the technical difficulty of center level height of Periodic Symmetric Struts Support (PSSS) by using the test in the field and reduce the high cost of testing, the method of the finite element analysis by considering thermal condition and the dynamic response is used and the center level height of PSSS is evaluated. Some relations for center level height changing process of PSSS were found and some parametric effects are obtained for the stability analysis of gas turbine by changing the number of struts support and angle.

Abstract: Engineering geology characteristics of No. 7 landslide located at Ciha Gorge is described and shear strength of the slip band soils is determined. Based on the above, unbalanced pushing force method is used to calculate the stability factor of the landslide the under different work conditions. It shows that the influence of the reservoir water level rising on the No. 7 landslide mainly includes two points: (1) water makes the shear strength of slip band soils reduced and thus result in the reduction of the stability factor; (2) the rising of reservoir water level also exerts water pressure to the surface of landslide body, and this is beneficial to landslide stability. Calculation results show that with the rising of reservoir water level the stability factor will experience beginning’s reducing followed by later increasing. The minimum stability factor in the process of impounding is 1.05 and it will be 1.08 when reservoir water level reaches to normal impounded level. This shows that No. 7 landslide will maintain elemental stability status in the all process of impounding.

Abstract: Taking a large hydropower station in Xinjiang Autonomous Region as an example, and based on the limited unit method, the structure and seism forces features and response rules of rolling concrete gravity dam under different construction conditions were studied. The purpose for the paper is to understand dam working status under the different design conditions, and to evaluate anti-earthquake safety capability. It is proved that the present findings should play an important significance in the development of rolling concrete dam construction technology. Key words: Rolling Concrete Gravity Dams, Limited Unit Methods, Static Force Analysis, Dynamic Features.